The present invention relates to a drilling tool for working in metallic material, more precisely a drill of the type that comprises a drill body having at least one cutting insert which defines the periphery of the hole, the drill being formed with one or more recesses extending in the longitudinal direction of the drill which recesses join to the outer and inner inserts, respectively, in order to serve as grooves for chip release.
At working of holes in metallic materials, problems arise with the high sound level caused by vibrations from the working and the machine sound. Hitherto used drills have not been provided with built-in/added damping devices formed in such a way that a suitable sound and vibration damping has been feasible. The essential thing is to be able to eliminate major parts of the vibration sound in the range that is uncomfortable to the ear. If possible, only the machine sound as well as the inevitable chip rattle which normally usually amounts to 74-76 dB should be left. However, without damping it is not uncommon that levels up to 130 dB have been measured. The proper machine sound feels more restful to the ear.
By the Swedish patent 468,930, it is, for instance, previously known to form a drilling tool with a partly vibration damping material, which has been applied in the recess of the drill's chip channels formed in the longitudinal direction. However, the hard metal borders applied according to the SE-468,930 have not turned out to give any suitable silencing of noise.